Bubo (in his final appearance in the programme) comes up from the trap door once again and starts a scunge fight.

After Berk bungs up a burst water pipe with a worm (though the worm works itself free), he has to get rid of a giant green flying sponge that came out of the trap door.

A purple, devil-like horrible thing with supernatural powers comes up from the trap door and starts casting annoying spells on everyone. Boni gets a body (and starts making goat noises), Berk changes orange, then red, then grows large, and Drutt continuously changes colour (green, yellow, and blue).

Berk, Boni and Drutt play Hide and Seek while the Thing Upstairs is on holiday, until a horrible custardy yellow monster comes up through the trap door and interrupts.

One of the Thing Upstairs' eyeballs falls down the trap door and Berk has to go after it.

Berk and Boni have problems with lots of creepy crawlies coming out of the trap door. In a parody of The Pied Piper of Hamelin, Berk uses a bugpipe to lead the creatures far away from the castle.

Berk loses patience with Drutt and throws him down the trap door, but he eventually decides to get him back by fishing him out. Unfortunately, Berk fishes out a red horrible thing that looks cute but, as Boni finds out, is actually anything but.

While Berk is giving the Thing Upstairs a slime bath, Drutt mistakenly pulls up a dinosaur-like thing from the trap door.

Berk throws rubbish down the trap door, filling it up to the top, but this summons ghosts that Berk thinks are after him.

There is a rotten smell in the castle cellar and Berk investigates, he finds the source of the smell; something pink and smelly came out from the trap door. Rogg comes up and tells Berk, Boni and Drutt that it is a "Lump", and it proceeds to make lots of noise.

The "Splund" of the title comes out of the trap door and teases Boni and Drutt, while Berk is sewing the Thing Upstairs' pyjamas.

It is the middle of winter and Berk has to mend the Thing Upstairs's heater. Rogg comes up from the trap door with a green fuzzy thing stuck to him. This is the last time that the Thing Upstairs is heard, with the following episode being the last time he is actually referred to.

A pink worm-like thing comes up from the trap door and eats Boni, Drutt's babies, the Thing Upstairs' dinner, and Drutt (in that order). Only Berk can rescue his friends and save the day.

The series finale. The red thing from episode one returns to cause chaos, and Rogg chases it into the swamps and confronts it.